Coal drier



y 1943- F. J. ANDERSON ETAL 9 COAL DRIER Filed April 7, 194].

fkAA/K c]; ANDERSON,

Adm/4.451. Tee's/mug,

1N VENTOR;

I ATTORNEYS.

Patented July 6, 1943 COAL DRIER Frank J. Anderson, Laramie, Wyo., and Michael Treshow, West Los Angeles, Calif.. assignors to Monolith Portland Cement Company, a corporation of Nevada Application April 7, 1941, Serial No. 387,232 4 Claims. (01. 34-429) invention relates generally to the art'of drying water saturated materials, particularly mineral substances such as coal or the like.

Although there are various known methods for drying mineral substances and the like, such high as 20%, approximately half of which ,ap-

pears as surface moisture on the individual particles. Therefore, it is a primary object of this invention to provide a new and improved economical means for drying water wetted materials such as coal or the like.

It is a particular object to provide a rotary drum structure designed to expose a great area of material passing through the drum to a current of air or hot gases also passing through the drum. It is also an object to provide a rotary drum structure designed to prevent ignition and carrying away of fine particles of coal or other material being dried.

These and other objects will be apparent from the drawing and the following description thereof. Referring to the drawing which is for illustrative purposes only;

Fig. 1 is a plan view, largely diagrammatic, of apparatus suitable for carrying out the invention;

. Fig. 2 is a sectional elevation of the apparatus ofFig. 1 taken on line 2-2 of that figure;

Fig. 3 is a fragmentary cross section on line 3-3 of Fig. 2; and

Fig. 4 is an enlarged cross section of the rotary drier taken on line 4-4 of Fig. 2.- A

More particularly describing the invention, the coal or other material is dried by the process which comprises essentially moving the coal in a divided state along a particular route and subjecting the coal to agitation. During the first portion of the route the coal is subjected to heat and to a current of hot air or other suitable dry gas which is caused to fiow in the general direction of the movement of the coal. During the latter part of the route over which the coal travels, the coal is subjected to a current of hot air or hot gases which are caused to flow in a direction opposite to the direction of movement of the coal. It is ofcourse to be understood that although the invention is particularly designed for drying coal and will be described with reference thereto, the invention is also suitable for drying other materials such as other minerals or the like.

Referring to the drawing, two drums indicated by numerals II and I2 respectively are provided for conveying the coal while it is being subjected to heat and hot dry gases. These drums are mounted for rotation in any suitable manner as for example by means of the flanges l3 and supporting rollers l4 and IS, the rollers being mounted upon suitableconcrete foundations l6. Any suitable means may be provided for rotating the drums and in this connection only ring gears I! have beenshown which may be engaged by a prime mover and any suitable intermediate gearing. The particular support and rotating means for the drums forms no part of: the invention. The drums are mounted at aslight inclination to the horizontal so thatmaterial introduced from the bin l8 through the chute. l9 intothe intake end of drum Will be caused to flow toward drum l2 and out thereof-at the end farthest from where the coal is introduced into the drum II. The discharge end of drum II is provided with an enlarged annular portion 20 provided with plates 2| forming pockets 22 for elevating the coal to a chute 23 which leads into the receiving end of drum l2.

In order to provide for heating the coal as it passes through the drums, housings or enclosures 25 and 26 are provided. These housings may be formed of any suitable material such as fire brick or other heat resistant material. The housings form chambers 25, 26' respectively adapted to receive hot gases for heating the portions of the drums which extend through the chambers. It is within the scope of the invention to provide any suitable type of joint between the rotatable drums and the stationary housings 25 and ,26 respectively in the regions 28 to seal the openings 29 in'each passing through drum II end of the'housings through which the drums extend in order to prevent undue escape of gases. Each chamber 25' and 26' may be provided with a stack or other outlet 30 as indicated in Fig. 1 so that there may be circulation of gases through the chambers. Any type of furnace may be provided for supplying the chambers 25,26'

with hot gases, such as 34 and 34 diagrammatically shown in Fig. 1 and connected to the chambers by pipes 21-21 respectively.

In order to provide for to a current of hot air flowing in the same direction as the coal, the receiving end of drum H is provided with what subjecting the coal will be termed an intake housing If surrounding that end of the drum. A' conduit 33 is provided connected with the .furnace 34 for supplying the intake-housing with hot gases.

In the region of the adjacent ends of the drums II and If an exhaust housing means 35 is provided which incloses such adjacent ends of the discharged coal leaving the drum It. This housing 42 is connected to afurnace 34' by means of conduit 43. Thus hot gases may be supplied to the discharge end of the drum i2 and will be drawn through the drum in a direction counter to the movement of the coal therethrough and will be drawn out of the drum in the region of the exhaust'chamber 31 and then exhausted through pipes 3|. and stack 40. The exhaust blower 39 provides a means of controlling the flow of the gases through the drums to attain the desired velocity.

' As the coal moves through the drum II it becomes increasingly dry and it is desirable toprevent the coal particles from freely falling from the sides and top to the bottom of the drum through the central portionthereofbecause of asaasaa also serve to provide additional heating surfaces within the drum for contacting the coal thereby aiding in the drying process.

In the operation of the device, the coal is introduced into the drum ll through the spout II at any suitable rate. The drums are rotated at a suitable rate and by reason of this and the fact that they are slightly inclined with relation to the horizontal the coal flows through the drums toward the discharge end. As the coal passes through the drum I I the hot gases from the furnace 34 introduced through conduit If and intake housing 32 flow through the drum ll, their velocity being controlled to a large extent by the exhaust blower 3!. During their passage through the drum lithe gases remove most of the surfac water from the coal. In this connection it was found impossible to remove-this surface moisture with gases flowing in a direction opposite to the flow: of the coal at this stage of the process. The coal is of course further heated by the fact that the intermediate portion of the drum I l is enclosed within the heating chamber Preferably the hot gases are introduced into the drum at a temperature of between 750 and 950 F.

At the discharge end of drum H the coal is elevated to the chute 23 and introduced into the receiving end of drum l2. As the coal flows through the drum I! it is subjected to a counterthe tendency of the small particles or fines to ignite and to be-carried away by the hot gases. It is also desirable to provide means for agitating and turning the coal material over during its passage through the drum in order to expose as large an area as possible of the material in the drum to the current of hot gases. To accomplish this the drum Ills provided withv a plurality of longitudinally extending plates .45 which are preferably, although not necessarily, arranged in staggered or checker board relation spaced inwardly from the inner surface of the drum. These plates are each mounted in the drum on supports 46 which may be secured to the plates and the drum in any suitable manner. Inverted v channel members 49 are also used to increase the movement of the coal or other material in the drum and to brace the supporting members 46. These channel members are secured to the drum and extend longitudinally thereof, their ends being positioned adjacent the supports 46 as shown. I

The plates 45 may be described as grouped in sets and when viewed in cross section, any set of plates forms an interrupted regular polygon. The plane of each plate is parallel to a tangent at the end of a radius of the drum perpendicular to the plate. With this construction as the drum is rotated, the plates 45 and the channels 49 pass through the body of the coal which tends to lie along the bottom of the drum and expose a fresh layer of the coal to the hot gases passing through the drum. At the same time, the rotation of the drumtends to elevate the coal up the side of the drum which is moving upwardly and the plates 45 tend to confine the coal to the region adjacent to become ignited or carried out of the drum by the current of air is minimized. The plates current of hot gases from the furnace34' which are introduced by means of the conduit 43 and intake housing 42. The blower 39 provides the necessary draught. In flowing through the drum ll mcst of the surface moisture of the coal is removed, while in flowing through the drum I2 the entrained water is removed.

In practice the process and apparatus have been found economically. suitable for removing the moisture from coal containing approximate- 1y 20% of water of which approximately half was surface water on th coal.

Although the invention has been particularly shown and described, it is contemplated that various modifications and changes may be made in the process and in the apparatus without departing from the scope of the invention and it is intended to cover such changes as come within the claims.

We claim as our invention:

1. In apparatus for drying coal or other material, two elongate drums mounted for rotation about their longitudinal axes at a slight angle to the horizontal, an end of one drum being adjacent an end of the other; meansfor rotating said drums; means for conveying material from one drum to the other in the region of their adjacent ends; means for introducing hot gases at the 0pposite ends of said drums and removing said gases at the adjacent ends of said drums; means for heating said drums; and means for substantially preventing the free fall of material laterally through the central portion of the drum receiving the material from the other drum including plates extending longitudinally of said drum spaced inwardly of the wall thereof.

2. In apparatus for drying divided material, a rotatable drum, and plates mounted in said drum in spaced relation with the wall thereof, the plane of each plate being parallel to a tangent at the end of a radius of the drum perpendicular to the plate, said plates each being disposed so as to have their outer surfaces opposite an adjacent portion of the inner surface of said drum, said plates being disposed so as to form an interrupted substantially regular polygon in cross section.

3. In apparatus for drying divided material, anelongate rotatable-drum, and a plurality of plates mounted in said drum in spaced relation with the inner surface of the drum, the plane an elongate rotatable drum, and a plurality of plates mounted in said drum in spaced relation to the inner surface ofthe drum, said plates extending longitudinally of the drum and being arranged in sets with the plates of one set extending to the cross sectional plane of the ends of the next adjacent set, the plates in each set being disposed so as to form an interrupted regular polygon in cross section and the plates in each set being staggered with relation to the plates in the adjacent sets the plane of each plate being parallel to a tangent at the end of a radius of the drum perpendicular to the plate.

FRANK J. ANDERSON, MICHAEL TRESHOW. 

